(Adds more reshuffled posts, context on Alassaf)

By Katie Paul and Tom Finn

DUBAI/DOHA, Oct 31 (Reuters) - Saudi Arabia appointed market regulator Mohammed al-Jadaan as its new finance minister by royal decree on Monday, replacing Ibrahim Alassaf, who had held the post since 1996.

Alassaf, 67, had been the last veteran member of cabinet to remain in a key post through a series of government reshuffles after King Salman assumed power last year, including one in May that replaced the long-standing oil minister.

He has been made minister of state and will remain a member of the Council of Ministers, as the Saudi cabinet is known, according to the royal decree.

The decree also appointed new chiefs for the Public Transport Commission and the Saline Water Conversion Corporation (SWCC), which both supplies water and generates electricity.

It transferred responsibility for consumer protection from the ministry for commerce and investment to the health minister, Tawfiq al-Rabeeah.

It was not immediately clear if Alassaf's removal would usher in a shift in Saudi economic policy, which is being crafted to a large degree by Deputy Crown Prince Mohammed bin Salman, who oversees the economic and defence portfolios.

The finance ministry is a key position in the world's largest crude exporter and the change is likely intended to support a wide-ranging economic reform plan to steward the kingdom through an era of painfully low oil prices.

Jadaan was formerly the chairman of the Saudi Capital Market Authority and had overseen the loosening of regulatory requirements as Saudi Arabia opened its stock exchange to foreign investors over the last year.

(Additional reporting by Mostafa Hashem and Reem Shamseddine; editing by Andrew Roche) ((Tom.Finn@thomsonreuters.com;))